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प्रश्न
What is PCR? Explain different steps involved in it.
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उत्तर
Definition: Polymerase Chain Reaction (PCR) is the process of in vitro amplification of gene of interest using a PCR machine.
Mechanism of PCR: At the start of PCR, all the requirements are mixed together in ‘eppendorf tube’ and the following operations are performed sequentially:
Step i: Denaturation
The reaction mixture is heated to a temperature (90–98o C) to separate two strands of desired DNA. This is called denaturation.
Step ii: Annealing
The mixture is allowed to cool (40–60o C) that permits pairing of the primer to the complementary sequences in DNA. This step is called annealing.
Step iii: Primer extension / Polymerization
The temperature (70–75o C) allows thermostable Taq DNA polymerase to use single-stranded DNA as template and adds nucleotides. This is called primer extension. It takes around two minutes duration.
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| Oil spill is a major environmental issue. It has been found that different strains of Pseudomonas bacteria have genes to break down the four major groups of hydrocarbons in oil. Trials are underway to use different biotechnological tools to incorporate these genes and create a genetically engineered strain of Pseudomonas - a ‘super-bug’, to break down the four major groups of hydrocarbons in oil. Such bacteria might be sprayed onto surfaces polluted with oil to clean thin films of oil. |
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